This invention relates to crimping tools, and more particularly relates to a novel and improved hand-held crimping tool for compressing fittings of different lengths into sealed engagement with cables of the type used in the cable TV industry.
Various types of hand-held crimping tools have been developed for attaching an end fitting or connector to the end of a coaxial cable in order to facilitate its connection into the terminal of a television set. I have previously devised jointly with others crimping tools of the type which are characterized by effecting the desired reduction in diameter or size of the cable end of the fitting into a generally circular configuration by applying an axially directed force to the fitting, as opposed to direct radial compression. Two patents of direct interest include U.S. Pat. No. 5,392,508 for AXIAL DEFORMATION CRIMPING TOOL and U.S. Pat. No. 5,743,131 for RATCHETED CRIMPING TOOL. More recently, I devised a pre-installed crimping ring as a means of applying axial force to the fitting with the aid of a crimping tool as set forth and described in detail in U.S. patent application Ser. No. 150,154 for END CONNECTOR AND CRIMPING TOOL FOR COAXIAL CABLE assigned to the assignee of this application and incorporated by reference herein.
Although the type of crimping tools described has been extremely effective in practice, there is a continuing need for a universal type of crimping tool which is self-compensating for slight differences in length of the various coaxial cable fittings presently on the market as well as differences in length resulting from manufacturing tolerances, dirt or wear. In achieving a secure, sealed connection between the fitting and cable end, the cable end is first drawn fully into the end of the connector and loosely assembled in the crimping tool as a preliminary to the crimping operation. The pre-installed crimping ring is characterized by being responsive to an axial or lengthwise applied force to impart radial compression to the connector in crimping it firmly against the cable end. It is therefore desirable that the tool be capable of absorbing or compensating for any force applied once the optimum degree of crimping is reached at the end of the crimping stroke. In this regard, it is also desirable that the manual force or pressure applied to the crimping tool during each crimping cycle will be translated into a progressively increased force toward the end of the cycle so as to overcome any increased resistance to crimping.